The present invention is utilized with carousel printing machines, such a machine comprising a plurality of print stations with stationary screen frames spaced circumferentially about the machine, and arms with work support pallets thereon rotatable into positions under successive stationary screen frames for printing a plurality of registering images on a workpiece on each work support pallet. Such machines are shown and described in U.S. Pat. No. 5,226,362 to Iaccino, et al., and in U.S. Pat. No. 5,806,422 to Alan Hamu.
A work support pallet must be in registration with respective screen frames at successive screen print stations spaced from the center of the machine in a generally circular arrangement. It has usually been required that work support pallets be removed and later re-mounted on machine arms in the process of alignment of work support pallets with screen frames.
A support pallet is removed, replaced with an alignment pallet, or pallet tool, then re-mounted and secured on the machine arm after registration with a screen frame. Time, labor and expense are involved in bolting the work support pallet, aligning the pallet tool, utilizing the alignment pallet for alignment with a screen frame, and removing and remounting the work support pallet on the arm.
The present invention provides the advantages of a pallet tool being quickly and conveniently installable and removable relative to a machine support arm, simplifying alignment of work support pallets with screen frames, and disassembly of work support pallets from the arms. Removal of the support pallet from the arm and later reassembly on the arm, after registration, are eliminated.
According to the present invention, a pallet tool is supported on a machine arm by engagement of a wedge member on the pallet tool in a groove member on the arm for pivotal movement of the pallet tool to a position beneath the screen frame. The pallet tool is a relatively rigid structure to provide rigidity and accuracy of alignment relative to a machine arm tool. With the work support pallet accurately registered relative to the machine arm, independently of the pallet tool, the pallet tool is moved into position in underlying relation with the work support pallet, the pallet tool maintaining alignment relative to the arm. Registration means, such as mutually engaging registration pins and openings, register the pallet tool with the screen frame.
The arrangement of the present invention is particularly useful where there is inadequate clearance or access above the machine arm.
U.S. Pat. No. 5,832,822 of Kaino J. Hamu, relates to a system wherein a pallet tool is pivotally accurately moved into position for registration with a work support pallet by the pallet tool pivoting above a machine arm and work support pallet. This application is incorporated herein by reference.